Water flows in a horizontal tube (see figure). The pressure of water changes by 700 Nm^-2 between A and B where the area of cross section are 40 cm^2…

Water flows in a horizontal tube (see figure). The pressure of water changes by $\displaystyle 700 \mathrm{Nm}^{-2}$ between A and B where the area of cross section are $\displaystyle 40 \mathrm{~cm}^2$ and $\displaystyle 20 \mathrm{~cm}^2$, respectively. Find the rate of flow of water through the tube. (density of water $\displaystyle =1000 \mathrm{kgm}^{-3}$ )